Casey: Johnson 'clear favourite' for Tour finale

Dustin Johnson is "clear favourite" for the PGA Tour Championship and the FedEx Cup this week, according to Paul Casey.

Johnson leads the way in the FedEx Cup rankings ahead of the season finale at East Lake, the U.S. Open winner 200 points ahead of Patrick Reed in second place.

Such is Johnson's advantage he could finish as low as 29th and still have a mathematical chance of lifting the FedEx Cup for the first time.

Adam Scott, Jason Day and Casey complete the top five heading into the tournament in Atlanta but the latter knows they will need a superb performance if any member of the chasing pack is to claim the title.

"My clear favourite has to be Dustin, the way he played at Crooked Stick was just brilliant," Casey told a media conference.

"I looked through the stats and Dustin doesn't ever get enough credit for other aspects of his game, everyone just focuses on his driving. I mean he was clearly a long way past everyone that week, but his wedge game and putting are just great, they really are.

"You need everything round East Lake so Dustin has to become favourite because his wedge game has become so good in the past 12 months, it's very tough to beat a guy like that when he plays good golf."

And should Johnson have a nightmare week, Casey believes Day will round off the year with victory, providing his back problems do not return.

He added: "Jason would be my second pick if he's healthy, feels like we haven't seen him play his best yet this year."